62 
ROOM XI. 
Nat. Hist. 
(somewhat similar to the plates under the toes of the 
Gecko,) by which these fish attach themselves to ships, 
rocks, and marine bodies. 
The second group of soft-finned fish consists of those 
which have no ventral fins ( Apoda ). The first family 
of these are the Eels (. Murcenidce ), which have a long 
slender body, covered with small scales sunk into a 
thick slimy skin. Their gill-flaps are small, surround¬ 
ed by the gill-rays, and covered with the skin, leaving 
merely a small tubular opening for the emission of the 
water. This structure enables the fish to live a long¬ 
time out of water. They have been divided into seve¬ 
ral genera, according to the teeth and the proportion of 
the fins. In most of the species, the dorsal and anal 
fins are long and united together; in others they are 
short and quite separate ( Moringua ); and in some 
they are entirely wanting. In one genus ( Synbranchus ), 
the gill-flaps only open by a single aperture in the un¬ 
der side of the neck. 
The Ophidium ( Opliidium) is very like the Eels, but 
its body is more compressed, and the gill-flap, formed 
as in the generality of fish, has a wide opening beneath. 
The rays of the dorsal fin are simple. 
The Gymnoti ( Gynmotidce ) have the gill-flap co¬ 
vered with a membrane, like the eels; but this mem¬ 
brane is open behind the pectoral fins. These fishes 
have no dorsal, but a long anal fin. In some the body 
is eel-shaped and naked, as in the Electric Gymnotus 
(Gymnotus electricus ). 
In the Carapi ( Carapus ) the body is compressed and 
covered with scales. The Gymnarchi ( Gymnarchus ]) 
differ from the Carapi, merely in having a long dorsal, 
and no anal fin. 
The Morris ( Leptocephalus ) is very peculiar for the 
exceeding thinness of its body, which resembles a 
riband, and is nearly as transparent as glass; its fins 
are scarcely visible, and its intestines occupy merely 
a very narrow line along the lower edge of the body. 
The 
